textproduct: Quad Cities

KEY MESSAGES

- The weather will become more active tonight into early next week with several chances for showers and thunderstorms. The primary threats are strong wind gusts and locally heavy rainfall which could lead to isolated flash flooding.

- Humid conditions are expected beginning Friday and lasting into next week. Hot temperatures in the 90s are possible next week, and when combined with the muggy conditions, could result in impactful heat indices.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 258 PM CDT Thu Jun 4 2026

Late This Afternoon through Friday Morning:

SPC mesoanalysis showed an increase in low-level WV transport across the Central Plains into portions of the Midwest so far today, with PWATs now up to ~1.3" across the far western outlook area. Much higher PWATs (1.7"+) reside off to the west across eastern Kansas into southwest Iowa. The drier air is hanging on along/east of the Mississippi River where PWATs are under 0.8". At the surface, southerly winds have been gusting 20-25 mph and dewpoints have increased significantly since yesterday, ranging from the upper 40s in the east to near 60 F in the west.

Increasing instability and large scale ascent through this evening will support the development of scattered showers and storms across the northwest portions of the area (especially W/NW of Cedar Rapids) after 7-8 PM. A few stronger storms are possible given SBCAPE of 1000+ J/kg and DCAPE between 500-1000 J/kg. Weak deep layer shear under 30 kts will be the limiting factor for organized severe storms. The coverage of showers and storms will increase tonight into early Friday AM (40-90%, highest north and west of the Quad Cities) as more organized activity emanates out of northwest Missouri and southwest Iowa, associated with a mid-level shortwave trough.

Locally heavy rainfall (1-2"+) is possible where repeated rounds of storms track through and this is most favored across the northwest counties. The HREF mean QPF has approximately 1-1.5" by early Friday morning to the NW of Cedar Rapids, with the HREF LPMM showing the potential for localized values over 2" if repeated rounds of storms were to occur in this area. Amounts will gradually drop off further to the east in the counties along/east of the Mississippi River. Due to dry antecedent conditions, overall flash flooding threat is low but still possible on an isolated basis given 3 hr flash flood guidance across the northwest between 2.5-3". Average storm motion will be to the northeast around 30 mph, but the eastward progression of the clusters of showers and storms will be rather slow. This will lead to a likelihood for storms to track over the same area through the night.

Friday Afternoon through Friday Night:

The first round of showers and storms should gradually diminish and push east of the area through the mid to late morning hours, leaving in its wake a more stable air mass. Thus it will take time for the atmosphere to recover and anticipate highs in the lower to mid 80s, but with much higher humidity compared to recent weeks with dewpoints well into the 60s/near 70 F. This will build SBCAPE to 2000-3000 J/kg by late in the day. Deep layer shear continues to look weak with values under 30 kts along and south of I-80, but could be a little higher to the north.

CAMs have been inconsistent on timing and placement of convective redevelopment Friday PM with a general consensus that storms will form along a west to east draped boundary near and south of I-80. The trend is for this activity to focus more into Friday night (mainly after 7-8 PM). However, as mentioned, confidence is low on the details. Moderate to high instability/moisture will promote quick upscale growth with slow storm motions potentially resulting in a localized flash flood threat. PWATs upwards of ~1.85" are supportive of hourly rain rates of 1-2" with the strongest storms. Additional clusters of showers and storms may move in from central Iowa late Friday night. The heaviest rain from this event may end up falling over a west to east swath that is only a tier or two of counties wide, with much of the rest of the outlook area receiving much lower amounts. SPC has continued with a Slight Risk (level 2 of 5) for severe storms roughly along and west of the Mississippi River (main threat locally damaging winds) and WPC has a Slight Risk (level 2 of 4) for flash flooding.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 258 PM CDT Thu Jun 4 2026

High pressure is forecast to build into the area at the surface and aloft Saturday night into Sunday before another shortwave lifts across the area Sunday night into Monday. This will bring the potential for another round of showers and storms to the area Sunday afternoon through Monday morning. There could also be the potential for heavy rain with any of these storm systems as model show PWATs near 2.00 inches Sunday night.

Beyond Monday night, an Omega Block tries to redevelop across the CONUS as 500 MB ridging builds back into the Central Plains and a closed low sits off of the East Coast and another in the Northern Rockies. Models differ on the placement of the ridge across the Great Lakes. This leads to differences in locations of shortwave activity traveling up the western side of the ridge. If the center of ridge is to our east, there may be several chances for showers and storms as disturbances lift northeastward into the Upper Great Lakes and if the ridge is centered closer to the area, it will be hot, humid, and dry. Ensemble guidance appears to favor broad ridging centered into the Upper Midwest shunting the better precipitation chances to our northwest.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 645 PM CDT Thu Jun 4 2026

Most TAF sites to be VFR early in the fcst period, before a line of showers and thunderstorms moves in from the west becoming more widespread after 05z. There will be some sctrd precursor cells ahead of the main line that may get into the VCNTY of CID and DBQ before then. Once the precip activity arrives, there will be bouts of more MVFR CIGs and precip reduced VSBYs into Friday morning. There may even be pockets of IFR CIGs and VSBYs late tonight through mid Friday morning. As the precip and lower CIGs move out by late morning or midday Friday, expect a return to VFR conditions for the afternoon and mainly precip free. Winds will be tricky through much of the period. Tonight they will be generally from some southern component, but with a sfc trof and rain/storm outflows, there will be some variability with temporary fluxes to the northwest. Southwesterly sfc winds will try to take over again with gusts as Friday progresses.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.